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Bipin C

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Safe Remote Server Reboot Guide

#devops #security #cloud #linux

For Ubuntu Desktop with Docker and Cloudflare Tunnel

This guide ensures your remote server comes back online automatically after a reboot when you have no physical access to the machine.

Prerequisites

Your server should have:

  • Docker with containers using restart: unless-stopped
  • SSH server enabled
  • Cloudflare Tunnel for remote SSH access
  • (Ubuntu Desktop) Auto-login configured

Pre-Reboot Checklist

Run these commands on the server via SSH before rebooting.

1. Check Docker Starts on Boot 

sudo systemctl is-enabled docker
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Expected: enabled

If not enabled:

sudo systemctl enable docker
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2. Check SSH Starts on Boot 

sudo systemctl is-enabled ssh
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Expected: enabled

If not enabled:

sudo systemctl enable ssh
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3. Check Container Restart Policies 

docker inspect --format '  - {{.Name}}: {{.HostConfig.RestartPolicy.Name}}' $(docker ps -q)
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Expected: All containers should show unless-stopped or always

4. (Ubuntu Desktop Only) Configure Auto-Login

Check if you have a desktop environment:

sudo systemctl status gdm3
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If GDM is active (Ubuntu Desktop), configure auto-login:

sudo nano /etc/gdm3/custom.conf
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Add under [daemon]:

[daemon]
AutomaticLoginEnable=True
AutomaticLogin=your-username
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Apply changes:

sudo systemctl restart gdm3
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Verify configuration:

cat /etc/gdm3/custom.conf
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Note: The keyring warnings (gkr-pam: couldn't unlock the login keyring) are normal and won't affect SSH or Docker.

Quick Verification Script

Run this single script to check everything:

echo "=== Pre-Reboot Check ==="
echo "Docker enabled: $(sudo systemctl is-enabled docker)"
echo "SSH enabled: $(sudo systemctl is-enabled ssh)"
echo ""
echo "Running containers:"
docker ps --format "  - {{.Names}}: {{.Status}}"
echo ""
echo "Restart policies:"
docker inspect --format '  - {{.Name}}: {{.HostConfig.RestartPolicy.Name}}' $(docker ps -q) 2>/dev/null || echo "  No containers running"
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Expected output:

=== Pre-Reboot Check ===
Docker enabled: enabled
SSH enabled: enabled

Running containers:
  - n8n-cloudflared: Up 33 hours
  - n8n-prod: Up 33 hours (healthy)
  - n8n-dev: Up 33 hours (healthy)
  - n8n-postgres-prod: Up 33 hours (healthy)
  - n8n-postgres-dev: Up 33 hours (healthy)
  - cloudflared: Up 36 hours

Restart policies:
  - /n8n-cloudflared: unless-stopped
  - /n8n-prod: unless-stopped
  - /n8n-dev: unless-stopped
  - /n8n-postgres-prod: unless-stopped
  - /n8n-postgres-dev: unless-stopped
  - /cloudflared: unless-stopped
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Safe to Reboot Checklist

Check Required Status
Docker enabled on boot enabled
SSH enabled on boot enabled
All containers restart policy unless-stopped or always
Auto-login (Ubuntu Desktop) Configured for your user

Reboot Procedure

Step 1: Reboot the Server 

sudo reboot
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Your SSH session will disconnect immediately.

Step 2: Wait

Wait 2-3 minutes for:

  • Server to boot
  • Auto-login to complete (Ubuntu Desktop)
  • Docker service to start
  • Containers to start
  • Cloudflare Tunnel to establish connection

Step 3: Reconnect 

ssh myserver
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Step 4: Verify

Once connected, verify all containers are running:

docker ps
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All containers should show Up X minutes status.

Troubleshooting

Can't reconnect after 5 minutes

Possible Cause Solution
Docker didn't start Needs physical access to check
Stuck at login screen Auto-login not configured (Ubuntu Desktop)
Tunnel container failed Check with docker ps when you regain access
Network/ISP issue Wait and retry

Preventive Test (Optional)

Before rebooting, test that containers restart properly:

# Stop all containers
docker stop $(docker ps -q)

# Wait a few seconds
sleep 5

# Check if they auto-restart (they won't - you need to start them manually after stop)
# This is expected - "unless-stopped" only auto-starts after daemon restart, not after manual stop

# Start them manually for this test
cd ~/cloudflare-tunnel && docker compose up -d
cd ~/n8n-stack && docker compose up -d

# Verify
docker ps
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Docker User Permissions

If Docker requires sudo, add your user to the docker group:

sudo usermod -aG docker $USER
newgrp docker
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Verify:

docker ps
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This persists across reboots. The newgrp command is only needed for the current session.

Summary

Safe to reboot when:

  • ✅ sudo systemctl is-enabled docker → enabled
  • ✅ sudo systemctl is-enabled ssh → enabled
  • ✅ All containers have restart: unless-stopped
  • ✅ (Ubuntu Desktop) Auto-login configured

Reboot command:

sudo reboot
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Reconnect after 2-3 minutes:

ssh myserver
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